As a horizontal articulated wafer transport robot used for transporting a wafer in semiconductor manufacturing, a robot having first and second parallel links is known. In a conventional wafer transport robot, a double link mechanism is configured by sharing one of four arms constituting a first parallel link as a common arm with a second parallel link to transmit an operation of the first parallel link to the second parallel link symmetrically. The transmission of an operation from the first parallel link to the second parallel link is performed by meshing a gear fixed to an end of a drive arm in the first parallel link with a gear fixed to an end of a driven arm in the second parallel link.
In another conventional wafer transport robot, an operation of the first parallel link is transmitted to the second parallel link by rotation of a belt extending between a pulley fixed to an end of a drive arm in the first parallel link and a pulley fixed to an end of a driven arm in the second parallel link.